1. Field of the Invention
The present invention generally relates to a V-type engine equipped with a turbocharger, and more particularly to such an engine having a turbocharger positioned between two banks of the engine.
2. Description of the Related Art
When a mechanical supercharging device such as a turbocharger is attached to a V-type engine, the turbocharger is often located between two banks of the engine in order to effectively use a space between the banks.
Japanese Patent Application Laid Open Publication No. 5-1564 discloses a V-type engine equipped with a mechanical supercharger situated between banks.
Because a rotor shaft rotates at a very high speed in the mechanical supercharger, it is necessary to feed an oil to bearings of the rotor shaft for lubrication and cooling. In general, an engine oil is used as this lubrication/cooling oil. A pump, oil passages/pipes and the like for recirculating the oil in the engine are also utilized to deliver the oil to the rotor shaft bearings.
Specifically, an oil conduit is branched from a cylinder block, cylinder head or other oil delivery part(s) and extends to an oil inlet of the mechanical supercharger. The oil is then caused to flow to the rotor shaft bearings.
However, if bolts for connecting the oil conduit and mechanical supercharger become loose, or the oil conduit is damaged by solid particles accidentally admitted to the oil conduit, then oil leakage may occur. The leaking oil drops to a valley between the two banks (referred to as "interbank valley").
An oil drain is generally formed in the interbank valley so that the leakage oil is promptly discharged from the engine. In reality, however, some oil unavoidably remains in the interbank valley. For instance, the oil adheres or sticks onto the interbank valley.
In the meantime, a turbocharger (particularly its turbine and associated parts) is sometimes heated to a very high temperature such as about 700 to 800.degree. C. during operation, and vibrations of the engine and vehicle body may cause the oil remaining on the interbank valley to spatter to the mechanical supercharger. This should be avoided.